Disk differential



Nov. 14, 1939. D. s. DE LAVAUD DISK DIFFERENTIAL Filed lay 17, 1938 2 Shuts-Sheet 2 0 mm ssusmm m2 LAVAUD e-r= 9mm, ome r ATTORNEYS Patented Nov. 14, 1939 uN-i'rao sun-:

PATENT OFFICE msx'nu'raarm'rmi, [minim scum?! de Lavaud, Paris, France was... mm,

In France friction members, which arev heldresiliently pressed, being arranged between a check which is secured to the driving'shaitand asliding ring secured to said loose sleeve and havingslopes on which bear ballsor the like which bear on the other hand on slopes provided on an axially fixed medial ring which .is angularly secured to the driving shaft,the differential as a whole being preferably symmetrical relative to said ring. According .to the present invention, the ,two pressure rings, which are arranged on eitherside of the medial driving ring, are normally spaced apart from each other by a resilient device .such.

as an axial spring which bears on shoulders provided on said pressure rings and causes a certain pressure between the iriction members.

According to another: feature or the present invention, the two, pressure rings are angularly connected to each other 1 but with a certain amount of play, so that one of ,said rings can rotate relatively to the other a sufli'cient amount for said ring to cease exerting a pressure onthe disks and consequently allow the .cbrrespond'ingdriven shaft to rotate loosely whereas the other driven shaft continues to be driven by the driving shaft. f

In an embodiment which appears to be advantageous for the time being, the connection between the pressure rings is obtained by mesmof claw coupling having'a certain amount of play between ,the teeth as indicated above. 1

According to the invention the teeth may have straight flanks or flanks that ireainclined at a. suitably chosen angle for totally or partially compensating the wear of the friction disks.

The present invention also covers a number of particular points which will become. apparent 5 in the ensuing description taken in conjunction with the accompanying drawings'which is only given by way 01 example and in which:

Fig. 1 is a view in axial section '01 a difierential constructed according to the invention. 5 Fig. 2 is a section according to line IIII of Fig. 1, 1 mFlgl. 3 is a section according to line 1II--III of 8- Fig. 4 is a section according to line IV-IV of Fig. 1.

1m, Serial No. 203,341 May 21, 19:7

2 cum. (on. 14-38%) Fig, 5 is a partial sectional view along V--V of Pig. 1, the rings being assumed to be developed. Fig. 8 is a partial sectional view along VIVI of Fig. 1, the pressure rings being'assumed to be developed and the teeth of the claw-clutch being 5 straight flanked.

Fig. 7 is a view corresponding to "Fig. 6, the teeth of the claw-clutch having inclined flanks. In the various figures of the drawings, the

same reference numerals designate the same 10 members. A driving shaft or propelling shaft I which is journalled in a case not shown is provided. with a worm Q or the like which meshes with a gear 5. Said gear 5 is secured by bolts 3 to two identical drums 1 and 9, respectively hav- 15 ing hubs 0 and III in which are respectively journalled co-axial shafts l5 and I6, Said shafts are grooved at their end and identical bushes l1 and I8, which are likewisegrooved, are-fixed respectively to the ehdsoi the shafts i5, and ii. The 20 periphery of the bushes l1 and L8 is grooved.

A ring I! is angularly and axially secured to the drums I and 9 and inside the latter, by any suitable means suchas keys on projections 20 provided at the periphery of the ring I9 and 25 engaging in suitable recessesprovided in the lateral edges of the drums I and 9. Inside the drums I and 9 and on'ei'tiier side'pf the ring IS, are loosely mounted two sleeves 23 and 2i respectively located opposite the grooved bushes I] and 30 ll. Said sleeves 23 and 24 are internally splined. Between the. sleeve 23 and the bush H are arranged friction disks 25 and 21 which respectively alternate with and are angularly secured to the bush I1 and the sleeve '23. Similarly, between the 35 sleeve 24 and the bush I 8 are arranged friction disks 2Q and 28 which respectively alternate with and are angularly secured to the bush l8 and the sleeve 23.

Between the extreme disk 25 and the ring I9 is interposed a pressure ring29 which is angularly secured to the sleeve 23 but can. move axially; similarly, between the extreme disk 26 and the ring I. is interposed a ring 30 which is angularly secured to the sleeve 24 but can move axially. The two rings 29 and 30 are angularly connected to each other but with a certain amount of play which allowsthem a certain angular movement as will be explained hereinafter.

For purpose and in the present embodi- 5o merit, the rings 29 and are respectively provided with lateral teeth 29 and 32* which cooperate together like a claw-coupling which has a certain amount oi play. The teeth or dogs 29 and 20' may have straight flanks as shown in 55 Fig. 6 or have inclined flanks as shown in Hz. 7 for the purpose which will be explained hereinafter;

Furthermore, said rings 29 and Il are respectively provided with shoulders 29 and 39" between which is interposed a spring 33 which tends to bring into contact with a certain amount of friction, the disks 25 and 21 on the one hand, and the disks 26 and 29 on the other hand.

On each of the faces of the ring l9 and on the face located opposite each of the rings 29 and 30, are provided respectively conical recesses or slopes 31 and 39 on the one hand, and 40 and 4| on the other hand. Between said slopes 31 and 39 and 40 and' 4| are respectively arranged balls 43 and 44. Said conical recesses and said balls are distributed over the periphery of the rings as is better shown in Figs. 3 and 4.

The operation is as follows:

When the driving shaft l is rotated, it drives, through the intermediary of the worm and worm wheel mechanism, the drums l and 9 which are secured to the wheel I. Said drums I and 9 in turn drive the medial ring I9. As the shafts l5 and ii are stationary and also the bushes l1 and [8, they brake, through the intermediary of the respective friction disks, the loose sleeves which remain stationary. There is therefore a relative angular movement between the rings 29 and 30 and the medial ring l9. The balls 43 and 44 move respectively between the slopes 31 and 39 and 40 and 4| and axially push back the rings 29 and 30 which thus firmly press the friction disks against each other thereby causing the driven shafts l5 and ii to be simultaneously and immediately driven whatever be the direction of rotation of the driving shaft I owing to the symmetry of the slopes, the extreme rings 25 and 29 being respectively pressed against the inner lateral faces of the drums I and 9.

If, for any reason, such as a decrease of resistance, one of the driven shafts, for example the shaft l5, tends to rotate faster than the shaft l9, the ring 29 which is secured to same by friction, will tend to rotate faster than the ring 30 and consequently than the medial ring l9, the speed of which cannot exceed that of the ring which is rotating at the lowest speed. Owing to the play which exists in the claw-coupling 29 and 30* provided between the rings 29 and 39, said ring 29 comes into the position shown diagrammatically in Fig. 5, in which the play has been exaggerated in order to facilitate comprehension, and consequently unwedges the ball 49 from between the slopes 91 and 39 and consequently releases the pressure between the disks 25 and 21, the ring 29 and the drum I, only allowing the residual pressure produced by the spring 39 to remain, which pressure is insufilcient to drive the driven shaft l5. As soon as the speed of the driven shaft ii decreases and owing to said residual friction and to the claw-coupling 29 and II, it will be seen that the sleeve 29 and consequently the ring 29 are braked relatively to the ring l9 and the ball 49 again pushes back said ring 29 owing to the movement -of said ball on the walls of the conical cavities 91 and 39.

A similar operation would be obtained for the shaft l6 if the latter tended to rotate faster than the shaft l5.

It will be readily understood that if the teeth of the claw-clutch have inclined flanks, when 10 What I claim as my invention and desire to secure by Letters Patent is:

1. In a friction disk differential gear, in combination: a drum rotated from a driving shaft, two coaxial driven shafts journalled in the said drum, a driving ring keyed on the drum and arranged between the said shafts, friction disks keyed upon the said shafts, two lateral rings arranged each upon a side of the driving ring, balls interposed between opposed notches provided in the said rings for axially moving the lateral rings 30 when occurs an angular displacement of the latter relatively to the driving ring, a hub upon one of the lateral rings protruding into the central opening of the driving ring and adapted to clutch with play with a similar hub of the other lateral ring, a spring interposed between the said lateral rings for spacing apart the same, and friction disks keyed upon the lateral rings and adapted for frictionally engaging the corresponding friction rings keyed upon the driven shafts.

2. In a friction disk differential gear, in combination:. a drum rotated from a driving shaft, two co-axial driven shafts journalled in the said drum, a driving ring keyed on the drum and arranged between the said shafts, friction disks keyed upon the sald shafts, two lateral rings arranged each upon a side of the driving ring, balls interposed between opposed notches provided in the said rings for axially moving the lateral rings when occurs an angular displacement of the latter relatively to the driving ring, a hub upon one of the lateral rings protruding into the central opening of the driving ring and provided with teeth having converging flanks and adapted to engage similar teeth provided upon a 

